Data from: Plant economics traits predict plant carbon allocation and responsiveness to arbuscular mycorrhizal fungi under varying precipitation

Most terrestrial plant species form symbioses with arbuscular mycorrhizal
fungi (AMF). However, the carbon (C) transferred from plants and the
nutritional and growth benefits they receive from AMF vary greatly across
species and environments. Currently, the extent to which this variation is
governed by plant functional trait syndromes remains poorly understood. To
address this, we conducted a 13C pulse labelling study with four grass
species inoculated with three AMF species under four precipitation regimes
to test whether plant C allocation and AMF-derived benefits can be
explained by functional traits representing specific axes of the plant
economics spectrum (PES). Our results demonstrate that the two main
dimensions of the PES differentially regulate the plant–AMF interaction.
The first dimension (PC1), strongly aligning with conservation-acquisition
strategy, was a predominant predictor of belowground C allocation and its
sensitivity to precipitation. The second dimension (PC2), defined by
variation in specific root length (SRL) that strongly reflecting a
collaboration strategy, primarily governed nutrient-related mycorrhizal
responses and their reaction to altered precipitation. Furthermore, path
analyses revealed that these traits exert direct and AMF
community-mediated indirect effects on the symbiosis. Synthesis: Our
results highlight that the positioning along plant economic strategies
provides a predictive framework for plant C-allocation and mycorrhizal
responses. By demonstrating that the trait-symbiosis coupling is modulated
by precipitation, this study advances our ability to predict how plant–AMF
interactions respond to environmental changes.